1. THCA Tsinghua University Physics Department, Engineering Physics Department, IHEP NAOC, CPPM (France) + Other Universities +… Charling TAO, Xiamen 2012 Computer Science Department Department of Precision Instruments and Mechanics Institute of advanced studies Geology department since 2001 Prof. Li Ti Pei

2. THCA students 3-5 undergraduate students every year Excellent ones: go for PhD in the US 2012 Hubble Fellows: 3 from Tsinghua Best undergraduate take advanced graduate classes: high energy astrophysics, cosmology, galaxy dynamics,,… 3-5 Master and 3-5 PhD students from Tsinghua and other Chinese U. 1 Irish PhD student.

3. 人才培养、学术奖励和学术交流 清华－高能所研究生学术讨论会

4. + Charling TAO. Understanding the Dark Universe. Multiprobe determination of cosmological parameters HXMT +… Prof. Li Tipei + Shang Rencheng + Zhang YouHong, Feng Hua, Zhou Jianfeng (Zhang SN) observations and analysis of X-ray binaries, ultraluminous X-ray sources and intermediate mass black holes, space instrumentation. SN observation and data analysis, cosmology Wang Xiaofeng +… LIGO Gravitational Wave Cao Jun Wei THCA Research Programs Broad range of data analysis efforts Sources of data: Chandra, XMM- Newton, XTE, ASCA, BATSE, EGRET, WMAP, SDSS, 2dF, NVSS, etc… Astrophysical objects: The Sun, X- ray binaries, gamma-ray bursts, galaxies, AGNs/QSOs, clusters of galaxies, large scale structures, CMB, SN, etc… 80 cm optical telescope in XingLong. - Gamma-ray bursts, supernovae, stellar oscillation DM direct detection (Yue Qian +…) Doug Lin exoplanets + environments +… Tian Feng Han Tao Theoretical particle cosmology Spectrographs ( Yang Huaidong+…)

5. A mysterious Universe ! Graph source: Wikipedia Definition:  c (  c =10 -29 g/cm 3 ) What we know is only 4% of the energy density of the Universe

6. The Accelerating Universe  Nobel Prize for Physics in 2011! Riess et al., 1998 Perlmutter et al., 1999

7. What is this Dark Energy? Cosmological Constant??? New form of « field/matter? » Quintessence? Unified Dark Matter? Modified Gravity/GR ? - Non minimal Couplings? - Extra-Dimensions? - Anisotropy/ inhomogeneity effects? - Negative energy? - …. How to distinguish them? - equation of state w(z) = p/  - structures growth factor - ??? w =-1

8. DE cosmology Future SNIa less powerful than BAO or WL for dw/dz ? (pending systematics) SNIa still purest geometrical probe. Other probes have structure growth factor effects Need to control systematics in all probes to reach 1% precision on dw/dz Power of combination  multiprobe analysis LSST, Euclid, + KDUST?

9. Supernovae type Ia Best known « standardisable » candles SNIa : 2 stars accretion (a white dwarf +…)  Chandrasekhar mass 1.4 M O Red giant White dwarf Chandrasekhar mass 1.4 M O

10. magnitude SN Ia are not exact standard candles! The light of SNIa explosions can be followed up for several weeks with telescopes SNIa Light curves

11. A mysterious Universe CMB 宇宙微波背景 (WMAP) SNe Ia LSS 大尺度结构 Universe is mainly dark ~72% DE and ~23% DM >10  effect now Definition:  c (  c =10 -29 g/cm 3 )

12. Cluster counts Supernovae Baryon Wiggles Cosmic Shear Angular diameter distance Growth rate of structure Evolution of dark matter perturbations Standard ruler Angular diameter distance Standard candle Luminosity distance Evolution of dark matter perturbations Angular diameter distance Growth rate of structure The concordance model stands quite strong! CMB Snapshot at ~400,000 yr, viewed from z=0 Angular diameter distance to z~1000 Growth rate of structure (from ISW)

13. SN + other probes

14. Power of Combinations astro-ph 0609591 DE Task force Caveat: Beware in case of different central values!  use other probes, especially necessary for equation of state not constrained by CMB

15. Combined constraints  equation of state parameter w around 5% statistical and systematic accuracy.  The statistical uncertainty on w from SNe Ia is now reduced to the level where systematic effects are comparable.  Today systematics are dominated by calibrations, dust corrections, and SNIa diversity Best studied with nearby SN spectroscopy Latest results SNLS3 years + WMAP +BAO

16. Current State of SN Systematics Photometric Calibration Uncertainties Dominate ! From Sullivan et al. 2011

17. The near future: 2012-2020 ? - SN: Improve systematics control to improve SN performance - BAO: Baryonic oscillations provide angular diameter distances: BOSS, eboss, Bigboss, PFS,… HSHS in China (Chen Xuelei) 21CMA version (Wu Xiangping) No systematics? - Weak lensing : DES, Subaru, … Understanding systematics, needs SPACE ? - Clusters - ….

18. The future (>2020): multiprobe DE projects KDUST

19. South Pole Dome A Kunlun Telescope will answer fundamental questions about the structure of the Universe. Wang Lifan Advantage: great seeing! Expect: 0.3 arc sec, eg space

20. Towards a large South Pole Dome A Kunlun Dark Universe Survey Telescope (KDUST)  Multiprobe measurements (SNIa, Weak Lensing, BAO, Clusters) for cosmology and ancillary science  First stage 2011-2014: 3 x 60 cms telescopes (AST3) - 1 AST3 installed in Dome A, 1st datataking in 2012.  THCA contribute to one AST3 and coordinates SN search  2.5 m KPATH (Kunlun Pathfinder): 2013-2016? - Collaboration with Australia, US and France  Larger (> 4m) KDUST: Timescale too early to define !

21. Opportunity in Jinping, Sichuan for direct detection DM detectors Yue Qian After Mentougou > 20 years ago… Great mountain coverage Tsinghua engineering physics department Leadership Many Underground Lab physics: Proton Decay, neutrinos physics, DM, … Possible size of cavity ?

22. What is this DM ? Modified Gravity Neutrino.WIMPs Weakly interacting massive particles 10-1000GeV Light Axions SIMPs Exotica MACHOs Black holes dustCold Molecular Hydrogen Warm Dark Matter?

23. My mission for Tsinghua  Understanding the Dark Universe: astroparticle, Cosmology and gravity physics –CMB analysis, SNIa,BAO, WL:. SNfactory, SouthPole, Euclid,. eboss/BigBoss, LSST, TMT, other? –DM : JinPing + phenomenology + future projects…  International collaborations (sino-french, Berkeley, USC, Lausanne, Sweden, EU,…)  Develop internal Tsinghua engineering collaboration with astrophysics More people (students, postdocs, faculty, visitors)? Analyse how to develop THCA  Develop collaboration with NAOC, IHEP  Develop collaborations with other astrophysics departments

24. Need for an astrophysics department in Tsinghua? Your experience is precious !

25. Our THCA experience Difficult to develop in a strong physics or engineering physics department where astrophysics < 10%. Promotion for your professors and staff is difficult  Democracy in the department: 2/3 positive votes! Window of opportunity: - Developing Chinese astrophysics context, -Support of NSFC and CAS - Tsinghua can now offer good salaries for tenure track positions -Tsinghua can offer housing (for a few years) -Critical size ~ 10-20 people ! -Proposal to Tsinghua University in 2013 ?

26. A personal view on Chinese astrophysics community Experience limited to astroparticle and cosmology Theory and data analysis has now reached international level Need more “creativity” and self-confidence Need more people in observation, instruments Better understanding and consideration for systematics studies and control This takes time, give less papers (? more technical ones), need collective team spirit – contradiction with high visibility first author competitive spirit ? Need different types of promotion and visibility Scientific revolution: concepts + technology

27. Long Live the Xiamen University Astrophysics Department ! + Nanjing U, PKU, Beijing Normal U, USTC, Jiaotong, Hebei, +… Thank you all for your hospitality and advices. We are looking towards closer collaboration Many thanks to Prof Lu for this invitation and opportunity to know better the Chinese astrophysics academic community Not yet 20, Prof Chen, but soon !